Nematic fluctuations at nonzero q in FeSe vs. Ba(Fe1-xCox)2As2

ORAL

Abstract

FeSe and Ba(Fe1-xCox)2As2 (Ba122) have several shared phase transitions such as the tetragonal-to-orthorhombic structural transition associated with nematic electronic order as well as a superconducting transition. There are also important differences, including magnetic order found in the Ba122 but not the FeSe compounds. Our recent inelastic X-ray and neutron scattering measurements of TA phonons in these compounds focused on anomalies in their dispersion. These anomalies reflect nematic fluctuations at nonzero q. We obtained nematic correlation length as a function of temperature from fits to these anomalous dispersions and found that it is similar in FeSe and Ba(Fe0.96Co0.04)2As2: compounds whose structural transition temperatures are close. In addition, we measured TA phonon dispersions and linewidths in optimally-doped Ba122 in detail. I will discuss the implications of the observed phenomena, focusing on the relation between nematic correlation length and the structural transitions, magnetic order, and superconductivity.

*DOE, Office of Basic Energy Sciences, Office of Science, Contract No. DE-SC0006939 (AM & DR)
HFIR, Oak Ridge National Laboratory, USA
Advanced Photon Source, Argonne National Laboratory, USA
RIKEN, SPring-8, Japan
ORPHEE, Laboratoire Leon Brillouin, France

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Presenters

  • Adrian Merritt

    • University of Colorado, Boulder

Authors

  • Adrian Merritt

    • University of Colorado, Boulder

  • Frank Weber

    • Karlsruhe Institute of Technology

  • John-Paul Castellan

    • Karlsruhe Institute of Technology

  • Alfred Q R Baron

    • RIKEN, SPring-8
    • RIKEN

  • Daisuke Ishikawa

    • RIKEN, SPring-8
    • JASRI/SPring-8

  • Ayman Said

    • Argonne National Laboratory
    • Argonne Natl Lab
    • Advanced Photon Source, Argonne National Laboratory

  • Ahmet Alatas

    • Argonne National Laboratory
    • Argonne Natl Lab
    • Advanced Photon Source, Argonne National Laboratory

  • Travis Williams

    • Oak Ridge Natl Lab

  • Rafael M Fernandes

    • University of Minnesota
    • School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA.
    • School of Physics and Astronomy, University of Minnesota
    • Physics, University of Minnesota

  • Joerg Schmalian

    • Karlsruhe Institute of Technology
    • TKM, Karlsruhe Institute of Technology (KIT)

  • Dmitry Reznik

    • University of Colorado, Boulder